[PVE-User] Ceph journal partition alignment

[Alexandre DERUMIER]

>>Now, so this doesn't happen "by default", I'm willing to make some tests 
>>to try to reproduce this and report where it belongs. If I recall 
>>correctly, Proxmox is using ceph tools for provisioning the OSDs? 

Yes, proxmox use ceph tools, but they create the journal partition only when it's on same disk than datas.

As I think you use a dedicated disk for differents journal, I think that you have create the partitions yourself (missaligned)


Here a parted result of an osd with data and journal (correctly aligned)


GNU Parted 3.2
Using /dev/sde
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p                                                                
Model: ATA INTEL SSDSC2BX01 (scsi)
Disk /dev/sde: 1600GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name          Flags
 2      1049kB  5370MB  5369MB               ceph journal
 1      5370MB  1600GB  1595GB  xfs          ceph data




El 04/08/16 a las 09:25, Eneko Lacunza escribió: 
> Hi all, 
> 
> We have recently installed a new node for our office cluster. This 
> node has an Intel S3610 200GB disk for Proxmox and Ceph Journals, and 
> 4x1TB HDD (3x1Gbit network). 
> 
> Installation was made with Proxmox 4.2 ISO. I have noticed that 
> journal partitions (sde4-sde7) are not properly aligned? 
> 
> Size: 186.3 GiB, 200049647616 bytes, 390721968 sectors 
> Label: gpt, identifier: CB415B43-CDF3-4D72-98BB-5A90367BD1FF 
> 
> Device Start End Sectors Size Type 
> 
> /dev/sde1 34 2047 2014 1007K BIOS boot 
> 
> /dev/sde2 2048 262143 260096 127M EFI System 
> 
> /dev/sde3 262144 125829120 125566977 59.9G Linux LVM 
> 
> /dev/sde4 125829122 136314881 10485760 5G unknown 
> 
> /dev/sde5 136314882 146800641 10485760 5G unknown 
> 
> /dev/sde6 146800642 157286401 10485760 5G unknown 
> 
> /dev/sde7 157286402 167772161 10485760 5G unknown 
> 
> I think those partitions should be 1M/4M aligned? Should I bother at all? 
> 
> Thanks 
> Eneko 
> 


-- 
Zuzendari Teknikoa / Director Técnico 
Binovo IT Human Project, S.L. 
Telf. 943493611 
943324914 
Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa) 
www.binovo.es 

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Alexandre Derumier 
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----- Mail original -----
De: "Eneko Lacunza" <elacunza at binovo.es>
À: "proxmoxve" <pve-user at pve.proxmox.com>
Envoyé: Jeudi 4 Août 2016 09:42:29
Objet: Re: [PVE-User] Ceph journal partition alignment

Hi again, 

Responding to myself, from intel docs: 
http://www.intel.com/content/www/us/en/solid-state-drives/ssd-partition-alignment-tech-brief.html 

"Intel SSDs have different page sizes depending on the model, but the 
current Intel Datacenter SSDs have 8 KB and 16KB pages. These pages are 
then organized into 
blocks." 

The doc then continues to recommend a 4KB filesystem alignment, and 1M 
partition aligment. 

Now, so this doesn't happen "by default", I'm willing to make some tests 
to try to reproduce this and report where it belongs. If I recall 
correctly, Proxmox is using ceph tools for provisioning the OSDs? 

Thanks 
Eneko 

El 04/08/16 a las 09:25, Eneko Lacunza escribió: 
> Hi all, 
> 
> We have recently installed a new node for our office cluster. This 
> node has an Intel S3610 200GB disk for Proxmox and Ceph Journals, and 
> 4x1TB HDD (3x1Gbit network). 
> 
> Installation was made with Proxmox 4.2 ISO. I have noticed that 
> journal partitions (sde4-sde7) are not properly aligned? 
> 
> Size: 186.3 GiB, 200049647616 bytes, 390721968 sectors 
> Label: gpt, identifier: CB415B43-CDF3-4D72-98BB-5A90367BD1FF 
> 
> Device Start End Sectors Size Type 
> 
> /dev/sde1 34 2047 2014 1007K BIOS boot 
> 
> /dev/sde2 2048 262143 260096 127M EFI System 
> 
> /dev/sde3 262144 125829120 125566977 59.9G Linux LVM 
> 
> /dev/sde4 125829122 136314881 10485760 5G unknown 
> 
> /dev/sde5 136314882 146800641 10485760 5G unknown 
> 
> /dev/sde6 146800642 157286401 10485760 5G unknown 
> 
> /dev/sde7 157286402 167772161 10485760 5G unknown 
> 
> I think those partitions should be 1M/4M aligned? Should I bother at all? 
> 
> Thanks 
> Eneko 
> 


-- 
Zuzendari Teknikoa / Director Técnico 
Binovo IT Human Project, S.L. 
Telf. 943493611 
943324914 
Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa) 
www.binovo.es 

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